The invention relates to a device on a motor vehicle with an internal combustion engine as the drive source and an accelerator pedal and transmission means for controlling the power of the internal combustion engine.
In controlling the power of internal combustion engines, problems can occur in traveling operation by the fuel and/or air-metering or control member remaining open as a result of faults such as, for example, sticking, tightness, breaking of the restoring spring, and the like within the power control system (accelerator pedal or transmission means), and thus the internal combustion engine unintentionally delivers power.
The object of the invention is to reliably exclude with simple means the possibility of the internal combustion engine unintentionally delivering power.
This object is achieved by a switching system in conjunction with fuel control means to prevent engine operation above idling power under certain circumstances. The switch, according to the invention, can be provided either directly on the accelerator pedal plate or at the connection of the transmission means (accelerator cable, accelerator linkage), ensures that the internal combustion engine delivers power only when the accelerator pedal is actuated by the operator. On the other hand, if the load on the accelerator pedal is relieved by the operator, the fuel-metering member, a throttle member in the intake line or the ignition of the internal combustion engine is controlled via the switch, and thus delivery of power exceeding the idling power is prevented. The switch actuating force F.sup.S has to be smaller than the actuating force F.sup.L of the power control system. Thus, when the accelerator pedal is actuated the switch is activated first and only then is the power control element or the metering member actuated.
The idling switch normally arranged on the throttle valve part of the combustion-air intake pipe of the internal combustion engine can be used especially advantageously in a motor vehicle with an internal combustion engine with overrun cut-off. This substantially increases the reliability without extra expenditure on switching parts. The internal combustion engine can be operated on no load, because the overrun cut-off does not act here. However, if the speed of the internal combustion engine increases, for example if the restoring spring in the power control system has broken off and consequently the throttle valve moves into the open position, the overrun cut-off--because the idling switch of the overrun cut-off remains deactivated--becomes effective and interrupts the fuel supply. The internal combustion engine cannot therefore deliver power exceeding the idling power.
Two exemplary embodiments of the invention are described below in greater detail.